A case study on improvement of an air conditioning system

A Case Study on
Improvement of an
Air Conditioning
System
Ms. Arpita Roy.
Ms. Rajashri Ghosh.
Mr. Soumyodeep Mukharjee.
Mr. Sandip Palit.
DEPARTMENT OF INDUSTRIAL ENGINEERING AND
MANAGEMENT
WBUT IN-HOUSE

1
IDENTIFICATION PROBLEM: Discussed on: 11.03.15
Persons Present:
 Ms. Arpita Roy.
 Ms. Rajashri Ghosh.
 Mr. SoumyodeepMukharjee.
 Mr. SandipPalit.
Discussion start
Ms. Rajashri proposed:
 Many people think that window air conditioners are not that efficient because they
are installed in the window. Also they are not very popular because in the winter
they let the cold air get inside your home.
 Windows air conditioning systems offer a lot of great options for those who have
installed central hot air systems.
 Window air conditioners are able to ensure a proper ventilation at all times, even
when the device is off.
Proposal of Ms. Arpita:
 Window air conditioners are used for ventilation on the central hot air system
because the ducting is already installed. The installation process is very easy, and
with the ducting in place, it’s even easier. There are two main parts of the unit: one
will be installed outside – the condenser, and one inside. The copper tubing will link
the two components.
 The unit will need to be powered by electricity, so after you have installed the units,
you can connect it to an outlet. Then the air conditioner is ready to be used.
 There are also a few drawbacks that window air conditioners have. If you do not
have a central hot air system that required ventilation, you will need to buy a special
cover for the unit. This way you will prevent the cold air from the outside entering
your house.

2
Mr. Sandip says:
 Also, the installation of the central cooling and heating system can be quite difficult.
The ducting is a big problem as sometimes there may be no room for it, and without
it the contractor cannot install the air conditioner. So before considering buying the
system, you should call a professional and ask for his advice. He will tell you
whether or not to invest in this type of air conditioner to buy another one.
Mr. Soumyodeep includes:
 Perhaps the most significant disadvantage of the portable air conditioner is its
limited range. A portable unit will generally cool only a small space, such as a single
room. The cooling output is likely to be less than a window unit and far less than
central air conditioning.
 Unlike central air, window AC units cool specific spaces or rooms at a time. They
tend to be more energy efficient because they don't run throughout the house
constantly, and you can focus on the areas that need to be cooled instead of cooling
your whole home. AC window units are also great because they're portable, so you
can take them with you when you move.
After the discussion it is conclude that there are several problems in the existing cooling
system. And they have to nullify with a better design. The points or the problems which
have been taken as the final note from the discussions to develop a new idea are:
1. Strange Noises
2. Not very versatile. Window units require a window to the outside and wall units
require an exterior wall to work.
3. Ugly. Most window and wall air conditioners aren’t nice to look at.
4. Security problem. A window unit could be an easy entry point into your home for a
burglar.

3
IDEA DEVELOPMENT: Discussed on: 12.03.2015
Person present:
 Ms. Arpita Roy.
 Ms. RajashriGhose.
Since there are some problems detected of the Window AC Unit, So
we choose to consult about each and every problem once at a time.
Proposal of Ms. Rajashri:
We need to deal with the problem of Strange Noises. So I think to
reduce noise we have to check the fan of the evaporator is okay or not. For a fan to work
properly, it will need to be kept clean and to be properly maintained. So My proposal to
check and change of design of the blowing system.
Proposal of Mr. Sandip:
May be if the fan motor is not properly lubricated, it can result in a
loud persistent noise.
The front grille of a window air conditioner needs to be removed on a
regular basis to clean the filter. These grilles are usually held in place by a simple locking
mechanism. If the grille is not put back properly, or the locking mechanism is defective or
damaged, it can vibrate and cause a lot of noise. So we need to check and redesign is
recommended for the betterment.
Proposal of Mr. Soumyodeep:
Window air conditioner units are pretty heavy, have lots of moving
parts and are precariously mounted on windows. As a result, these units are prone to a lot
of vibration if they have not been mounted correctly. Touch the sides of the window frame
on which the air conditioner is mounted. If they are vibrating excessively, you should call
the people who installed the air conditioner and ask them to fix it so that the vibration is
minimized. So He thinks by reducing items or parts which is not actually needed with the
evaporator may help to reduce noise.

4
The next thing to think about is the problem with the usage of the
AC unit in versetile areas. That means window ac unit must require some spaces not only
in inner wall but also in outer wall.
The problem is specifically is the outdoor part of the window ac must
need some outside areas where the hot air can going out into the atmosphere. So we need
spaces inside and outside of the wall.
We can remove this problem if we can split the total unit in two very
parts. We can see that the main problem regarding the ac unit is the compressor part
which ejects the hot air as well as some water.
So we can make the compressor as a different part which can kept
in a different position can solve the problem may be.
The next thing to concern is about the aesthetic beauty of the Air
conditioning Unit. I think that if the ac unit looks better then the marketing of the AC will
be higher.
Many people doesn't want to buy the AC just because it's look ugly
as well as the size of the AC unit is huge. We have to look forward about reducing the size
and make a complete different shape which looks better than the normal Window AC.

5
If we split the AC system like what we have discussed before about keeping
the compressor part of the initial system then there will be a lot of space which will not
require. So I think the system will be smaller than the previous one.
We should also look after about the fins and the evaporator part of the
system unit. By changing into suitable designs which can suit and looks better as well as
can work better. The total systems have to be redesigned.
One of the most important point to discuss about is the security of the
owner while he is installing the Window AC unit. Since there have to cut the window or a
portion of the wall so there must be an option of theft by the place through which the AC
unit have been kept.
Yes I agree with you and I think this is a huge problem to think about.
Another thing is when the unit is mounted in a secret place like Bank
Locker or any other restricted place then at the time of maintenance there will be a lot of
problems facing both of the concerned owner and the service man.
Another thing is to check about the energy efficiency and power
consumption. In window Ac unit these thing have not been taken care of carefully.

6
I completely agree with this and i think if we need to make the AC unit
more energy efficient we have to change the compressor type. Basically the Window AC
uses Rotary and Reciprocating compressor. If we change these compressors in to the scroll
one type then I think this can be change the total system.
This can be a good idea about changing the compressor. If we use
scroll instead of Rotary then the noise problem will be reduced. So that is a good proposal.
So here we conclude our discussion. I think all of the problems have
been discussed. We are now looking forward to the Idea Screening session from where we
can make a suitable design which can replace the existing AC unit and make a better one.

7
IDEA SCREENING: Discussed on: 14.03.2015
Person present:
 Ms. Arpita Roy.
Concluded ideas:
1. We'll split the compressor part out of the main Window AC body. There will be an Indoor
Unit which includes the Evaporator part. The outdoor part includes the compressor,
condenser and the expansion valve.
2. We need to work on the the shape of the Split Ac unit. The Shape of the Indoor Unit will be
thinner and light in weight.
3. We'll use Scroll Compressor instead of Rotary Compressor.

8
DESIGN DEVELOPMENT: Discussed on: 21.03.2014
Person present:
 Ms. Arpita Roy.
DESIGNS:

9
PROTOTYPE DEVELOPMENT: Discussed on: 24.03.2015
Person present:
 Ms. Arpita Roy.
Required Raw Materials with quantities:
INDOOR UNITOUTDOOR UNIT
SL.NO COMPONENTS QTY SL.NO COMPONENTS QTY
1 Fan/ Blower 1 1 Compressor 1
2 Fan Motor 1 2 Fan 1
3 Filter 1 3 Fan Motor 1
4 Louvers 1SET 4 Refrigerant As Per
Require
ment5 LED Display 1SET
Miscellaneous
SL.NO COMPONENTS QTY SL.NO FASTNERS QTY
1 Evaporator coil APR
1 NUTS APR
2 Condenser coil APR
2 BOLTS APR
3 Capacitor APR
3

12
FUNCTIONS:
 Fresh Air.
 Less Pollution.
 Cooling.
 Heating.
 Moisture control.
 Humidity Control.
 Purification of Bad Air
EVALUTION AND TESTING: Discussed on: 02.04.2015
Person present:
 Ms. Arpita Roy.
Functionality testing report: After testing the AC unit all the functions are matching to
their desired conditions. So here by, the Unit of the Air Condition is declared to be Okay in
functionality and it’ll work properly as desired.
Reliability testing report:
 Heating Mode Tests: Heating mode tests included steady-state, cyclic, and defrost
tests. The purpose of the steady- state tests is to acquire a sufficient amount of data
to develop accurate performance maps. The test matrix was designed to optimize
test time while testing each unit under a variety of operating conditions. Under
certain operating conditions in heating mode, frost will accumulate on the outdoor
heat exchanger and the unit must enter a defrost cycle to melt the accumulated frost.
The unit’s efficiency during defrost operation is taken into account in HSPF
calculations. MSHPs don’t often cycle between on and off due to the variable speed
control, however, the HSPF calculation is also dependent on cycling performance

13
degradation. For each operating condition, various fan and compressor speeds were
tested. Fan speed was set using the high, medium, or low setting on the unit’s
remote control. The compressor speed was varied indirectly by varying the load
provided by the psychometric chamber and the thermostat setting on the unit’s
remote control. A majority of the tests were conducted at an indoor temperature of
70°F. Several test points at different indoor temperatures were added to capture the
dependence of return air temperature on the heat pump performance. Herrick
Laboratories tested the Fujitsu unit first. Slight improvements were made to the
steady-state heating mode test matrix for the Mitsubishi unit as more was
understood about MSHP behavior. The cyclic and defrost tests are required to
calculate the HSPF as outlined by Air-Conditioning, Heating, and Refrigeration
Institute (AHRI) Standard 210/240 (AHRI 2008). The default return dry-bulb
temperature for heating mode is 70°F and the default return wet-bulb (WB) for
cooling mode is 67°F. The final entry in the test code is included if the test was
conducted at an intended indoor condition other than the default value.
 Cooling Mode Tests -Cooling mode tests included steady-state and cyclic tests.
Similar to the heating mode tests, a variety of operating conditions were tested to
best characterize the performance of the system under different indoor and outdoor
temperatures, fan speeds, and cooling loads. The indoor wet- bulb temperature
becomes an important variable when switching to cooling mode. A majority of the
test points were conducted at 80°F dry-bulb and 67°F wet-bulb indoor condition
since this is the indoor operating condition used by the SEER rating procedure for
steady state tests. Additional test points were added to the FE12NA test matrix after
it was determined more points were needed to accurately model the cooling
performance.

14
PERFORMANCE TESTING REPORT:
 Energy efficiency ratio (EER):
An air conditioner with higher EER saves more
energy and is more efficient – which translates into higher cooling capacity with lesser
power consumption. The EER is the ratio of rated cooling capacity Btu/h [W] and rated
power input (in watts) in standard conditions. The efficiency of an AC directly affects the
operating cost of an air conditioning system. The efficiency ratio reflects the total
cooling/heating capacity that we can get out from an AC system per unit power that we
input to it. You can reduce your electricity consumption by using higher star-rated
products available in the market (5 for most efficient to 1 star for least efficient).
 Net total room-cooling capacity:
Total room-cooling capacity is the available capacity
of the air conditioning unit for removing heat from the space to be conditioned. A higher
capacity means it is better in terms of cooling and dehumidifying effect.
 Power consumption (input power) (watts):
Air conditioners were rated between 1,420 watts and
1,680 watts for input power. Input power should not be more than the declared value by
the manufacturer. Since the AC may run for hours during summer days, this becomes a
very important aspect for users as their electricity bill will be affected accordingly.
 Maximum operating conditions test:
The purpose of this test was to prove that the air
conditioner was capable of operating satisfactorily under maximum operating conditions
when outside temperature was 46 °C and supplied voltage was 207 volts and 253 volts (+-
10% of 230 volts.) For all the brands, the air conditioner was run in the test condition for
two hours. After two hours the air conditioner was switched off for three minutes, after
which power was restored. Voltage rise on switching off the AC was less than three per
cent. The AC started without any rattling or abnormal sound. There was no physical
damage to the test unit. It ran continuously for one hour after start, and there was no
tripping.
 Noise level:
When operated with rated voltage and rated frequency, the noise level
in the indoor side and outside was measured. Maximum sound level for the indoor unit
should not be more than 58 decibels (dB) and for the outdoor unit it should not be more
than 68 dB. All the brands were within limit.
 Net dehumidifying effect:
This is the total capacity of the unit for removing latent heat from
the space to be conditioned.

15
 Net total sensible effect:
This means the capacity of the unit for removing sensible heat
from the space to be conditioned.
After testing in both Heating Mode and Cooling Mode it is found that the AC unit is okay.

16
FINAL DESIGN: Discussed on: 02.04.2015
Person present:
 Ms. Arpita Roy.
List of Items which are in-house Manufacturing:
1. Condenser
2. Compressor
3. Evaporator
4. Copper Coils
5. Fan & Fan Motor
List of Items which have to be exported from Vendor:
1. Filter
2. Louvers
3. LED Display
4. Refrigerant
5. Nuts
6. Bolts
7. Remote Control

18
Compressor Selection
IDENTIFICATI
ON PROBLEM:
Discussed on:
11.03.15
Persons
Present:
 M
s
Compressor Coil
IDENTIFICATI
ON PROBLEM:
Discussed on:
11.03.15
Persons
Present:
 M
Fan & Fan Motor
IDENTIFICATI
ON PROBLEM:
Discussed on:
11.03.15
Persons
Present:
Selection of Condenser
IDENTIFICATI
ON PROBLEM:
Discussed on:
11.03.15
Persons
Present:
 M
s
.
Selection of Blower
IDENTIFICATI
ON PROBLEM:
Discussed on:
11.03.15
Persons
Present:
 M
s
.
A
r
p
i
Selection of Fin
IDENTIFICATI
ON PROBLEM:
Discussed on:
11.03.15
Persons
Present:
 M
s
.
A
r
p
Selection of Louvers
IDENTIFICATI
ON PROBLEM:
Discussed on:
11.03.15
Persons
Present:
 M
s
.
A
r
PROCESS FLOW CHART OF MANUFACTURING FOR DESIGN:
**** 1, 2, 3,4,5,6 are indicating Inspection in the ongoing process
and Testing of the product if required.
RefrigerationTesting
Final Assembly
Assemblyof O.D.U
Assembly of I.D.U
Exporting sub assemblys
from vendor ( viz. LED
Display, Remote Contorl )
Assembling Evaporator
with
Copper Coil
Assembling Condenser
with
Copper Coil
Assembling Compressor
with
Copper Coil
1
2
3
4
5
6

19
PACKING & DESPATCH: Discussed on: 02.04.2015
Person present:
 Ms. Arpita Roy.
Primary Process: Covered with Plastic Packet and thermo-col.
Secondary Process : Card Board Box pack with accessories ( LCD remote to turn on and
off the AC Cord, 3 m Copper Wire, Drain Pipe, User Manual, Warranty Card )

20
Markings on product and packaging:
a) Manufacturer’s name and address
b) Type and model and serial number
c) Refrigerant and charge
d) Rated voltage, phase, frequency
e) Nominal cooling capacity
f) Power consumption at rated conditions
g) Nominal current at rated conditions
h) Dimensions
i) Energy labels on both the units as well as packaging

21
FUTURE DEVELOPMENT: Discussed on: 07.04.2015
Person present:
 Ms. Arpita Roy.
FUTURE Development As this is the first stage of development. Some of the ideas is still
cannot be applied on this project because of some problems and time limitation. So that, I
will leave it for the other stage of development either for my own project or other student.
There are a few things that can be improvised this portable air conditioner in the future
development. The electrical energy consumed can be reduced by setting the smart
portable air conditioner to operate automatically. This can be simply done by placing
motion sensor that can sense the motion of people and turn the power on then it will of
when there is no people in that area. Besides that, other improvement that can be made on
this project is to increase the strength of the cold air flow with creating a new design with
adding more or replace high power of blower. The high power of blower can produce
strong air flow which can increase the length distance.

22
CONCLUSION
As a conclusion, we can conclude that a cheap portable air conditioner is
achievable and can be marketable in reality. The portable air conditioner made
satisfies the basic air conditioner functions for cooling purpose. The air
conditioner has been tested to its functions and reliability of its design. Human
factor taught us that human may feel comfortable because of several factors.
One of the factor is the temperature, as we all noticed that some of the country
especially country with equatorial climate such as south East Asia have hot
temperature climate. Because of that, air conditioner become one of the
important thing that help people to feel comfortable with reducing
temperature in their surroundings. We can conclude that this smart portable
air is marketable. With the decoration design such as tree is the frequent that
been used in Malaysia during events. It is because it shows the concept of
nature and many people the concept. But then, mostly event such as on stage
has very limited space to place air conditioner. So, this smart portable air
conditioner is possible to reduce space for air conditioner with placing in
decorations space which is near to the user. The smart portable air conditioner
is also proved that it is making people easier to move the air conditioner with
the wheels and simple assembling system. It could make user faster to move
and setup the air conditioner.

A case study on improvement of an air conditioning system

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